SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '472defc41770135bf5b46bfbfdcd3551b8eaa296ba313b45a4b02d9e361c87e6' 
  AND token = 'NM1YC1S+7gSDXRKFDyHJD11JSm7vRUfFECuZEwibWQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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