SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53dd94fb974f8aa3452e6ff80963b58b712d2694ccd98abab7a72787beae7016' 
  AND token = 'RJDQ47fUYesR4XuyKhxx3TI2wwEfSjT8FC7AfHcaokk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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