SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa6a9576a9175e5ab7ba4d29688c059bef1e3ca43f3f109ce2434c99d9fb378b' 
  AND token = 'IDhwYJsRwgdWr++/3SFD31hFbxFsaXcTZkZKeIRcb34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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