SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20fd849f9eeeb573211acf4c0017971e4a83e2b838c7efb4cd69538d259a1640' 
  AND token = 'qYPKRQO3A5xmuisiwtkPINz+0lnfehRVUX3Cai523iY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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