SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e79cfd4de005cc11a18af6b9a829b8415a6e432f5e20c1d5751eacbe682f4b4' 
  AND token = 'xt8nTmSScBc+mUKnPU115hJ70szD6h1O6BbhoDTdMbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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