SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ad827c8316666a2e1633cb120863e78b4f8cf5772a791e2f086c78ec29e8abf6' 
  AND token = 'UyG0SKSi7jyM5DUNL16riczNdzDwrqj/HmjkeMAFnsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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