SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccbbae8b630d501cbec99705d45b799f7f76f73f7f261899c86858428f1f4f7e' 
  AND token = 'aSl03LrHaB8U3yV7ww+xtG507QPbbuClWz/lLid9bXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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