SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7328bc5345634badd4c1d904a00e5fff8e10cde1e0231325f0ed67c7e354527f' 
  AND token = '7uO4tJg99gxzl00rtFOx5XmS/sPn5Ik0DtEIx8HZjjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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