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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f70273c89cceaf69232004f6b93d775f86bbd2264d1615f5a0175a4969aad0bb' 
  AND token = 'qDtkc3SwKvlUjC2lrTkC2wo9NSvPbkjkQ3qTV9KiH1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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