SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e737aa3983eae956a76fe1acb0ecc2613884b515cf7d70f90e20104707f40d3c' 
  AND token = 'J3lJVrKevgcbMtpLHkVi0PctHM0WA83rFxvwpeTL0qc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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