SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '336caafe775de1e3d3d1bdc93b41842f73c1af38cff360e06d13fd50866591f2' 
  AND token = 'CFJLBwngnWTGMkXJxaq4PCLWDlNBdNMIJt1U9zmCunI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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