SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cd6796ca73ad906ccda25b6f576528e57de8db31a4f6788ef23d11a798d548b' 
  AND token = 'mibQyTbSkiyjZ5izCnq2ii3uEP1Wg3obMW+VLXyEins=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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