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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6338a229e89510e7db94240a8f9d9d292034f39e4780a5f48b03aa5bc521a24f' 
  AND token = 'eqhnHPK2j0Ctpny9bMrmA4jbChb6x6ZdFuH36Vb05aA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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