SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c63906b050d90055a9ff88232fa62f17a992d5b852daead8a575cb04e84ad3e' 
  AND token = 'YFsADsP7PBxiOrApgPjWc+PqZRJnsP7dPKZPpDBRmgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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