SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9887a59247fcc0488d7937375865a99112621309029fbca630c09283ef2dfb57' 
  AND token = '4OuXC5NFLdiPYjvMZNPWLR6Uq37Xw1nOkd7/LkKwW30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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