SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '412fb460fe8d02073054fdd1da71126d60697333712c41e2366b8c3b2f48be1e' 
  AND token = 'LEqWAlbXbJhxQeMAv9i2aifqPqNmqJEwuOsguVMRSvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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