SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cce59c890081a5c8ea0b3bd96d5f6957bc60288dfc5d88445eff098705302d7' 
  AND token = 'oMqSqyJtIdAU4inMxAeamO0JiSPcAuKcyPfUp3zIFrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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