SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63665f4c334541e2c975a9a8c21154bbdb8f8f9935a683234383b28c7ee78af3' 
  AND token = 'RPfU57DyeE458bhaItvM+nWWJDsEnXvJEWPSOJ27GAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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