SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '992d00b9130a60bfea5ce84753c639fab971a0428b3453607aa0e64a08e2b822' 
  AND token = 'ayYidaD71VfFHlZUfX9Jr1fi1umf8z2vwPVu5QhLJGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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