SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cae18b0399dfe23308f04c08fd2dc8e898a506482456dc78e7bf837547bdf63' 
  AND token = 'TsuZYBCCWauvRqgBIbVRePFxueYrcZ/N+SvsNsDMAK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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