SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '016dda6fde34be9de16d0011ca4cad0d45929f48155dfffd8fe23362064c78a3' 
  AND token = 'PFseBonCIcIWxsAwlvNavJs7Ea+GVjZuelye9RNprYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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