SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '394064f0ed4f24d0c95f56ed97d28280226e1cb76224e88cd5e4794ef86176f0' 
  AND token = 'KgF61pMcsWKDkjrASkxU38pNW3vbrleppSJlxW4KwY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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