SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8439b5d8d6a384db8803b3c5f310a7fbf84f0df1130320c4802108cc17e21aaa' 
  AND token = 'jIIg/060wLhvfBMqDpnLlOPaAlJdWiUJrbxeYsOS5JA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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