SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ce67f17976e422746ed2f291ac5301fca62f38d345a427288c72ce5b962df91' 
  AND token = 'eNBGpbH3DnyWwVcAEmyAyZBJfSSmxlbE8LP91oaKz5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}