SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c1881c1af9093abfb83d913ee4dd243000d31363b98177270ed3fc7c7988cfc' 
  AND token = '6oCtJ/Vn05vDsz01B43Yx7m6KYKV/NkHlquTvAVjBMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00086

JSON explain

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