SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c649e46ae59ea492d192c736dd32c813c2f060b8f63b556927acebe3525a08b' 
  AND token = '8UNvK7fTtkgc+MZjw4C3iEulqrBCBr/i8//vUVrdlIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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