SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f943acccc9024451cb8ad384675d1c0fed779b7a606c9bd49e0f5c9ef6376702' 
  AND token = 'o6kb3D/e+KurO/27nuQIGep7CNTod8+jk4/bV3YRnfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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