SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb6cee18dd295bb36901ed5c8eca1adfec5f19c89d902fb782622666deb7a46a' 
  AND token = 'RROxZ9ev3D3Bgu1xn8UecuQ2nG85f+4mwESzEuF5HMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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