SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac6c94e5b93c5086077cddf0e4f4f527f10fb8369c3a378db462adf580ba0947' 
  AND token = 'W+dH7QUVsEyJ5qaJM5QlLGv15Gsse1EVcLG7Fzn6pmw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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