SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c189801f0c0ca84a34b7429c99c61f3885d6890767217090de097a750f6c7f8f' 
  AND token = '8MpIsOPX2VJT4C+HLLoR931A21Vo9XB6PrEOIOAYHkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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