SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43b6bb6c06724e04c26dd283673658a5a28bb1e02fcedf07a5aa65a2f4965865' 
  AND token = 'O+cmwBUdBhpn24XRCNPwLWStUaE8l65IBE1htTJu+aA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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