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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '308f87847f9c61534ae67abb55a38301cf840f8a9c5fa74f94df860ecaba5d3e' 
  AND token = 'fiQaUga1jI7W7sk1i13KZMEupwNFaAmgMn1rcjDfVMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

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