SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b648aadf858e1d445453b1463fe30ecefca4a25437cc430caf2c025240db3121' 
  AND token = 'cTZmFFAnibPjECx/fbtMA+7UYtdfXp9VLPPhhpdylb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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