SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9042888bf02c73d908853fa7aa172653232368e817b86bd5ce90ccf8db935244' 
  AND token = 'XuMzoc2gIyLIkfmblkGoJlB+IdXHCuj25DKzW6vJyxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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