SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ea276c84b869bbd6fe524a52ca3c95e06db1342af1181d1734ab8fd2f40c65f' 
  AND token = '+PAjOr8Vu/+1/CvAxzcLcdnT3bGuVLd5qV1UgeLFKGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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