SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '397affaabe65f796434a45907e03b526f2d6bffda645edf4199bc443a4955351' 
  AND token = 'QU7z6TFlZsgYt1XgK0IRbQPnmLimnvsIFzEKr1n+kok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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