SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cd168453a303fc7b988b812de5afb4d094afb63308642ebe5e621fd743fd20f' 
  AND token = 'OFD9NV0NVv/Epl6zdSOjlEvqXIVIXAm9aNlvYt4/I7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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