SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eca9222079084860e98e36f22e48f4ddaa72fffa90320b16fce0fd8d7994206' 
  AND token = 'kq4UGFGSwNaZMeClBbCMpYLIbjQxMCxoRnhLtBFlNzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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