SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '103862e0e7176fc4bf83faa8b017dd7974c5253aa8e3260c570626458102426c' 
  AND token = 'MjXLet7uhsx8Wd5wwwemtqukhRFWsEzyudTRRLabPsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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