SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd591cf34cd6022468431cb3796eb86ce56da4a40c740befa1aea10d6074599ba' 
  AND token = 'kEVVnzhiDtSEUCbYK/KuLJNUvGyD9iZMjUDGLq2o88g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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