SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6248972232b401a0a8dd4b772a9e80ed7a99e22465a175f6028192c4e324ba63' 
  AND token = 'TinmDyjlrO6L9e1kw+fUKcJVmjrVraVdk9j71EA3aEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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