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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a12eb10f3b2a865f619c29735f8f824145f29204aa9365d73ac3e1194d2d66c6' 
  AND token = 'UUWmQdgGuX4cVN0BRqlctOSi1KE1zwykywgaCHLVUyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

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