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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a50dd29550ce33e4e16d3cd66af2aec51462a6bd4c28ef5126307058a81cff8' 
  AND token = 'l7zamYR2Vyjl5goFoj7TmHDfbdu5c5BYDSdmblUugjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

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