SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe17a5bdfd4a9985e118fcda4d60d8229c26558c7004011319ecc396e318e846' 
  AND token = 'ejVgfuZqW8Kzw3sbAJMWmiLBQ1CxJGXKv2hQgOFhPis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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