SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31f58631a49b36621869427f08398db05bc4da1141f8119136f028dce68f715f' 
  AND token = 'irlPkLmnNYnfaHff7RTOc5dV65YfyhiuWrYkQis+ZoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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