SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c25b0eea1993853554b5beea4cd9442c7b2911731f3dbb5758a24bcf99f0058a' 
  AND token = 'xjzi4FEeCvcr1F5eIaDXd/jMhDHdtB/gisz7E7Xev0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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