SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '409513603e1b7d46e1d511255f55b54d56909d3afbb09b309316aefecd78c776' 
  AND token = 'q32FZSijQapZV4NqVx+8TfGHGOQz8OaCNu2jD1iKqe4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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