SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '79ed1a3a2f2261151cb6fe8ebf425100c9933e700b9067132919317a7b9b7f64' 
  AND token = 'haZ/CMNZkxw0Nu+mDKdugxLVklA3lANyH8MqlVqYhsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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