SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d6d42eab141386a3786d7a8797badf3cff4638ca76e72b5001430ba999ea66b' 
  AND token = 'Hj8eLImpJ4xWorNUsQjnfm+/aStvk5w0UJJxolFXZkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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