SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b2172284013352b5e09e7f7f652cee94b505c4f5d68efeae53a3f18a7041062' 
  AND token = 'xZ96jtdGLXB+aTUF81P7BqEHkPXEwtuPDEzsfZioozw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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