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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a844abc916b300acc5cdf692ab39e92f444e1b75b7e39d832cc11231504c4fac' 
  AND token = 'b4udwsG0fyVD3rjeTNg6K23t8VaJdhFx2qZFoxpd698=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

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