SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00c7bb521cc00032319133c584bb9aa5364cc1be32904b436e53f235def0e80d' 
  AND token = 'U7Dp/VvuhMZaCb7pI5ujTIP6MVgze74YE3Ju7gVreiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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