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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71ff740aea368fc02b2433be0ddf67ab65e1b39b6ffa335d9efc06e7309325de' 
  AND token = 'hab2BeRf2Nmg72OHBiYkDFHBsnDjCJIa8cvV4GjilbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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