SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fddd408c1b6a1be2760f27825a58fbe94f47ceb81f9bf15ddea1c9054315c7ef' 
  AND token = 'sggnvsfvcJ9cNUoYNCf9NwK+eSnQ1voXSL+yundPpuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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