SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6621676b044fabf4835fbd20d61b750a8811590f59cd2e0b8a207cbe9b9e6732' 
  AND token = 'MHwfSRoRN7knMtLzd91lOZaEvSA/INb5Fl/ubZhoEiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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