SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '28d53035243067c1b400a5c0cc0b48a70beb2880ca719c38a276db2f5107d4f8' 
  AND token = 'MfDefiKHtAvRwRPrpXNgng2jZ+rpVk7Rg75L6+tBSbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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