SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8b18574b3da9279b1e156a3b0bfc2453feb822ff505c906873a22dfa573b3250' 
  AND token = 'isQk1xvYXZP2Grc34OF+vRTaoi5HDK6VNz0UtrfInmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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