SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3091367de5114af32ed824f69f21fdbc987ae439992aad0b500e3d9af8b7e71' 
  AND token = '0/086MlaAAd4qWs7ZRIQCUuQEs5/3r7XgEiO0dQpyJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}