SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74c856f175ee29355393651e49afa6ce03a15d37a9fe24b1369017c94c299650' 
  AND token = 'Vlc+a/rKtk2MLl3FfSTOwf5gZJGPa60W9dzjus5r+E4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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