SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6bdc1b7f07797371f3b498ac98fc24fcb62ab4ce4210c928adcce140f9755e0' 
  AND token = 'PXP6WhKeabgpcrmGjyI0BRsL7hQYDhRIHiV3Oa+VNhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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