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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4274a89f8992292eccb102bbc5db2157dae12c340b3610c1976f773a94ba83ca' 
  AND token = 'TKEfh8Aui3LmMAktlsut5uNG1WuytDleKxF4uLtUl4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE								Impossible WHERE noticed after reading const tables