SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '267d740831ed70494abaee98d822842764415ecdfdfc4abb154bea80340e3a95' 
  AND token = 'RUXfqx5Hd+APFCyPwkYvvhJ7FFGz2DQ7AAm80+PLaao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}