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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fe93dc1a39a2a904f12ee0a7f9ea5653a5054669986c1523a41366b2b5da938' 
  AND token = 'g0rmps7Ycqsx44EoG3pLd7Pi2TDWn3mELo2TMTzwcCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

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